1. Field of the Invention
The present invention relates to an optical analog-to-digital converter. More particularly, the present invention relates to a device that utilizes a laser, an intensity discriminating material, and a light detector to convert an analog input signal to a digital output.
2. Problems in the Art
Analog-to-digital converters (ADC) are well known in the art. Typical ADCs utilize silicon transistors. A typical ADC samples an analog signal and converts the sampled signal to a discrete value by methods that are well known in the art. Although silicon based ADCs function well at lower speeds, there are physical limits as to the speed at which conversion can be performed. A need exists for an ADC which can operate at a higher frequency. An ADC that utilizes the faster nature of light would improve over the speed offered by current prior art ADCs. Such an improved ADC is disclosed by the present invention.
3. Features of the Invention
A primary feature of the invention is the provision of a method and apparatus that converts an analog signal to a digital signal at greater speeds than those currently known in the art.
Another feature of the present invention is a method and apparatus that converts an analog signal to a digital signal using an intensity modulated laser, an intensity discriminating prism, and a linear detector array.
A further feature of the present invention is an apparatus which utilizes a crystal, having a varying index of refraction, for analog-to-digital conversion wherein laser beams of varying intensity are refracted to varying degrees, and the refracted beam is detected by a linear detector, which produces a digitized output from the analog input of the laser.
These as well as other features of the invention will be apparent from the following detailed description in conjunction with the accompanying drawings.
An optical analog-to-digital converter (ADC) comprises an analog input, an electromagnetic wave generator operatively connected to the analog input, an intensity discriminating material to refract an output electromagnetic wave, and an electromagnetic wave detector. Preferably, the electromagnetic wave generator is a laser and the intensity discriminating material is a prism. The electromagnetic wave generator must be able to produce an output wave of sufficient intensity to induce a change in the refractive index of the intensity discriminating material. The electromagnetic wave generator must also be able to produce an output wave of varying intensity, the intensity being dependent on the analog input. An intensity discriminating material is one that has a different index of refraction for electromagnetic waves of different intensities. The output from the electromagnetic wave generator hits the intensity discriminating material and is refracted. The electromagnetic wave detector detects the refracted wave and outputs a digital signal.
The method of converting an analog signal to a digital signal includes the steps of providing an analog input and generating an electromagnetic wave. The intensity of the electromagnetic wave is dependent on the analog input. The electromagnetic wave is passed through the intensity discriminating material. The electromagnetic wave must be of sufficient intensity to induce a change in the refractive index of the intensity discriminating material. The electromagnetic wave is refracted by the intensity discriminating material and is then detected by the detector, which outputs a digital signal.